Most Frequently Asked Questions & Answers
Q: Does my bath need to be cold in order to get decent sectioning?
A: Not necessarily. The "rule of thumb" is, the softer the tissue, the colder the bath.
The purpose of cold is to stiffen the tissue. Remember, you are not processing the tissue and embedding in paraffin nor are you freezing the tissue. The firmer tissues (e.g. muscle, heart, etc.) may very well be sectioned in a room temperature bath. Neural tissue etc. must be chilled in order to get decent sectioning.
Q: What is the best way to get my bath cold and keep it cool?
A: In most cases the use of ice cubes made out of the bath material (e.g. PBS) is quite satisfactory. Alternatively, the use of plastic encased water cubes (i.e. Those used on picnics etc.) may be used. However, there may be instances where an exact experimental temperature is required (e.g. some of the newer immunochemical procedures). There you may require the utilization of, for example, the refrigerated Vibratome 3000 where an exact temperature is selected and held +/- 1° C.
Q: Do I have to achieve a specific temperature when I chill my bath?
A: No. "Cold is cold" unless the experimental protocol calls out for a specific temperature. Most people just go for "Blood Bank Temperature", i.e. 4-6° C. Whether the exact temp is 2° or 8° doesn’t really matter in most cases.
Q: What variables do I have to work with to obtain good sections?
A: Four (five if you want to include section thickness)
The "Rules of thumb" are
By "trial and error" you play with the above to determine the optimum setting to achieve good sectioning of a given tissue at a given section thickness.
Q: My forward speed has been gradually changing. It seems to be getting slower (or alternatively, is not constant throughout the forward stroke). What is the problem?
A: Most probably the winding of the motor is beginning to fail. Replacement is relatively inexpensive and relatively simple. We include directions when we ship you a new motor. The Vibratome motor can be compared to a light bulb. One can last years, the next only months (at least six). The cost of a new motor is quite modest.
Also possible, but rare, is corrosion on the hardened steel rods of the carriage drive mechanism. If bath fluid is spilled through the openings where the carriage drive comes forward, it could impact on the rods, and cause corrosion spots on the rods. Parenthetically, splashing could also, short out the solenoid, short out the PCB, short out the motor. Be neat, don’t splash! Also parenthetically, if you are utilizing a nutrient media bath through which you are bubbling oxygen, bubble at the front of the bath, not the rear.
Q: At the end of the return stroke, I can hear an audible "clunk". What is wrong?
A: Nothing. In addition to the motor, the return stroke is "spring loaded". Sometimes, in some units this spring mechanism will "clunk" at the end. This does not affect form, fit or function. The critical stroke is forward- this must be even and reproducible.
Q:: My Vibratome just quit working. What are the most likely causes and what do I do?
A: Most probably it’s either the motor or the Printed Circuit Board (PCB). Obviously, however, the first thing to do is to check the fuse. If the fuse is blown, replace it. If the fuse is OK, the differential diagnosis is to determine if the instrument is vibrating. If when you switch to forward and you get vibration but no forward motion- it’s the motor. If no vibration and no movement it is most probably the PCB. Both the motor and the PCB are inexpensive and easy to replace. Parenthetically, it is more cost effective to simply replace the entire PCB than to determine which component on the PCB has failed and to replace it.
To repair Vibratomes, 3 options exist.
Q: My Vibratome enclosure is beginning to rust around the bath. I am afraid of spilled bath fluid leaking through. What should I do?
A: The degradation of the paint and subsequent rusting does not affect form, fit or function. The only way of leaking into the interior of the device is through the seal screw (four- one in each corner) or through the specimen height control assembly at the center of the bath. These openings are all seal-screwed, o-ringed and siliconed.
Paint degradation/rusting is aesthetic only. The most cost-effective approach is to pick up a can of spray paint at your local hardware store. The paint won’t be an exact match but should be close enough for aesthetic purposes.
Of course you can, if you insist, send the unit in and we can replace the case. This involves a complete disassembly and reassembly of the Vibratome and will cost you several hundred dollars.
Parenthetically, paint degradation/rusting is a function of housekeeping. Any spills etc. should be wiped up ASAP and the case should be wiped down on a regular basis.
Q: I just inherited an old Vibratome. It looks like hell and I don’t think it’s working properly. Can I trade it in for a new one or should I just throw it away?
A: Vibratomes are very user friendly for repairs and upgrades. Call TPI and discuss the options that exist for meeting your fresh tissue sectioning needs.
Q: I know something is wrong but I haven’t a clue as to what or why. What is my best approach?
A: Phone us! We will discuss your specific problem(s), ask the appropriate diagnostic questions, and offer you various options.
Historically and statistically half of the reported problems can be talked through via phone or FAX. By us sending you a part(s) with specific instructions of what to do and how to do it can solve another 30-40%. Historically, only 10-20% of "down" instruments have to come in to us for service.
Q: I am getting "thick & thin" sections, (i.e. first one really thin or nothing, the next one very thick or double what it should be; the next thin, the next thick, etc.) why? What can I do?
A: There are three causes of "thick & thin"
By far the most common cause of "thick & thin" is technique. Refer to all the technique comments. The most common technique problem is too shallow a blade angle when cutting "soft" (e.g. Fresh brain) tissue. Steepening the blade angle will cure the problem.
Next, the Carriage Block assembly can go out of alignment from a variety of causes-the discussion of which is unimportant here. Follow the Carriage Block re-alignment procedure.
The least common cause is worn or damaged Specimen Height Control Assembly. The diagnostic here is to see if you can hear/feel the detent clicks as the control knob is being rotated. If you cannot and/or the knob is frozen or difficult to turn, the Specimen Height control assembly needs to be serviced or replaced.
Q: Where and how often should I lubricate my Vibratome?
A: Never! The Vibratome is not, repeat, not a lubricatable device. Attempting lubrication will more often than not do more harm than good. The only exception is the motor, under one condition only. See the next Q&A.
Q: All of a sudden my Vibratome is "squealing" or making a grinding noise when I send it forward. Why and what can I do?
A: Occasionally our motors are not properly lubricated in production at the factory. This fact does not show up in our QC and the problem manifests itself only after some period of service. If you, the user, catch the problem early it can be solved as follows:
Q: All of the previous is all well and good but how much of a "rocket scientist" do I have to be in order to care for my Vibratome.
A: Not at all; Above all do nothing until we instruct you as to what to do. All of our parts, advice and suggestions are accompanied by what, why, when, where and how- instructions. Historically, we have found that virtually all research groups have one or more people who feel comfortable "diddling" with instrumentation-use them. Also most every institution has "in-house" service departments. If necessary you can utilize them for the more involved parts replacements.
Of course, you can always send the instrument into us for any reason. Your decision should be based on cost analysis and cost/benefit- not only in terms of dollars but also in terms of "down-time".
Q: Why does my old Vibratome appear to have more vibration amplitude than my new vibratome?
A: Over time, the metal in the Vibratome blade mechanism fatigues. This fatigue results in higher vibration amplitudes as it is much easier to move the metal. There are two methods which will allow your new Vibratome to get greater amplitude: 1. Solenoid re-alignment or 2. Shim Washers. Please see procedures as to how to perform either of these two options.
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Grabbed on 04:20, Fri, Aug 17, 2001